Let me share some knowledge from our good friends, the Baha'i:
"Not everything that a man knoweth can be disclosed, nor can everything that he can disclose be regarded as timely, nor can every timely utterance be considered as suited to the capacity of those who hear it."
With that on mind, how much sense would it have made for Kishimoto to start talking about all the technicalities of jutsu from the beginning? Especially since he isn't explaining to us directly, but to Naruto. He didn't just make it all up last month, read the chapters and you will see consistencies in hand seals which produce specific jutsu. It's only natural that since Naruto is advancing, he should learn more about the nature of chakra. Kishimoto was just waiting for an appropriate time to unload this information. This might not be true for everything however.
♥ of the cards!
No matter the genius, they all fall to mediocrity in front of the Uchiha!